wolverton@owu: Recent Episodes
Chris Wolverton
I forgot to press ‘record’ on the lecture this morning, so I’m sharing a lecture over the same topic from a previous semester, sorry! Slides: Photosynthesis
Somehow I’m already behind my schedule, so the first 20 min was finishing up some ideas from the first lecture, with the rest focused on atoms and chemistry. Slides: Atoms and Bonds
First day of class for Fall 2022, and today was an introduction and overview of the scope of the class. Slides: Intro & Overview
The nuts and bolts of how an mRNA is read and turned into a sequence of amino acids by the ribosome. Slides: Translation
This time we discussed the greater complexity of transcription in eukaryotes as well as the processing required to prepare the mRNA primary transcript for export from the nucleus. Then we changed gears and started discussing the steps involved in translating from RNA into a sequence of amino acids. Slides: Transcription and Genetic Code
We briefly reviewed the Beadle and Tatum results indicating that genes encode polypeptides, then moved on to discuss how the order of amino acids in a polypeptide chain is specified by the sequence of bases making up RNA. This sequence is “read” 3 bases at a time, which is called a codon, which specifies a … Continue reading "34. Genetic Code and RNA"
We reviewed the key points of replication and discussed a few major differences between prokaryotes and eukaryotes related to replication. We discussed the Beadle and Tatum experiment, an elegant demonstration of the one gene – one polypeptide hypothesis. Slides: How genes work
We talked about the evidence showing that DNA replication takes place in a semi-conservative manner, with each strand of the double helix serving as a template for the creation of a new complementary strand. Then we discussed the mechanism of replication, focusing on prokaryotes for now. Slides: DNA Replication
We looked at the 3 key experiments in the history of biology that pointed to DNA as the hereditary material, including the Griffith transformation experiment, followed up by Avery, MacCleod, and McCarty, and finally the Hershey and Chase experiment. Then we turned to the structure of DNA and how it encodes information. Slides: DNA Function … Continue reading "31. DNA Function and Structure"
This time we take our understanding of the basic principles of inheritance and see how they match with our understanding of chromosomes, then we look at how the process of crossing over promotes genetic recombination and independent assortment, even for genes on the same chromosome as long as they are far enough apart. Slides: Chromosomes … Continue reading "30. Chromosomes and Mapping"
This time we walk through the basic applications of Mendel’s principles, thinking about the connections between his data and the processes of meiosis and fertilization. Slides: Genetics
An introduction to the key ideas and insights gained as Mendel studied the inheritance of 7 characteristics of garden peas. He collected large quantities of data by scoring the phenotypes of offspring from carefully controlled cross-pollination events, using inductive reasoning to arrive at a set of principles of inheritance that we still largely accept today. … Continue reading "28. Mendel & Inheritance"
Meiosis is the special form of nuclear division that cuts the ploidy level (number of versions of chromosomes) in half. This is the process that enables sexual reproduction to occur by maintaining the same ploidy level afer fertilization as before meiosis. Meiosis is made up of 2 rounds of division with no intervening synthesis phase, … Continue reading "27. Meiosis"
The cell has various checkpoints in place to prevent itself from prematurely progressing through the cell cycle. Some of these checkpoints monitor external factors, others internal state, and one is based on a physical cue. When one or more of these cell cycle checkpoints fails, uncontrolled cell division can occur, which can lead to tumor … Continue reading "26. Cell cycle regulation and cancer"
The stages of the cell cycle, including G1, S, and G2, which together make up interphase, and mitosis and cytokinesis, along with details of each of those. Slides: Cell Cycle
An overview of some of the major players in signal transduction pathways within the cell, including phosphorylation, MAP kinase cascades, second messengers, and some of the downstream targets of signal transduction. Slides: Signal Transduction
An introduction to cellular signaling, including the kinds of signaling, the properties of ligands, and the major kinds of receptors found in or on the surface of the cell. Slides: Cellular Signaling
We finished up some details on C4 and CAM pathway plants, which overcome photorespiration by separating the activity of Rubisco from the initial carboxylation reaction, then we spent some time practicing answering some review questions. Slides: Photosynthesis
A tour of the light-independent, or carbon reactions, of photosynthesis, which use the ATP and NADPH produced in the light reactions to reduce atmospheric CO2 to carbohydrate. These reactions take place in a metabolic cycle in the stroma of the chloroplast. Slides: Photosynthesis
An introduction to the interdependent reactions of photosynthesis, including an overview of how light interacts with matter, then a bit of a deeper dive on the photochemistry and electron transport reactions of photosynthesis. Slides: Photosynthesis
A detailed look at feedback regulation in glycolysis, and the processes of pyruvate oxidation, the citric acid cycle, electron transport system, and chemiosmosis, all of which lead to the synthesis of ATP. Slides: Cellular Respiration ATP synthase video
An overview of cellular respiration, including the link between the concept of energetic coupling and the stepwise series of enzyme-mediated reactions; detailed discussion of glycolysis. Slides: Cellular Respiration
How the principles of thermodynamics apply to chemical reactions in the cell, including an overview of Gibbs Free Energy, exergonic and endergonic reactions, and how enzymes help to lower the activation energy of a reaction. Slides: Energetics and Enzymes
An introduction to some background concepts for our discussion of metabolism, including anabolic vs. catabolic reactions, entropy, energy, and work, and the laws of thermodynamics. Slides: Metabolism Concepts
A review of diffusion as the driving force for much of membrane transport, including some of the factors that affect the rate of diffusion; introduction of passive transport, including direct and facilitated, along with active transport. Slides: Membrane transport
An overview of the functions of the plasma membrane followed by a discussion of the structure of the phospholipids and other components that make up the membrane. Slides: Plasma Membrane
An overview of the kinds of connections that form between cells and their functions. Slides: Cell Connections
A tour of the components that make up the cytoskeleton, the internal network of dynamic proteins that give the cell mechanical strength and play a vital role in various cellular functions. Slides: Cytoskeleton
Wrap-up of our discussion of the endosymbiotic theory, quick tour of mitochondria and chloroplasts, then we discussed the nucleus and endomembrane system of the eukaryotic cell. Slides: Nucleus and Endomembrane System
An overview of the similarities among all cells and the contrasts between prokaryotic and eukaryotic cell types, ending with an introduction to the endosymbiotic theory for the origin of eukaryotes. Slides: Prokaryotes and Eukaryotes
An introduction to the study of cells, including some historical landmarks and concepts, a discussion of the limits on cell size imposed by diffusion, a discussion of optical resolution, and an introduction to several kinds of microscopy important for the study of cells. Slides: Intro to Cells
An overview of the nucleic acids, including the structure of nucleotides, DNA, and RNA, and how complementary base pairing works. Slides: Nucleic Acids
An overview of proteins, including their function and the 4 levels of organization that produce protein structure. Slides: Proteins
Introduction to the lipids, which are non-polar and hydrophobic. Lipids include fats and oils, waxes, certain vitamins, pigments, and steroid hormones. Slides: Lipids
Overview of carbohydrates and the three major classes: monosaccharides, disaccharides, and polysaccharides. Slides: Carbohydrates
Study tips for this class; Characteristics and properties of the carbon atom that make it well-suited for biological molecules; Overview of functional groups; Bond geometry and isomers; Dehydration synthesis and hydrolysis reactions. Slides: Carbon
The structure, properties and characteristics of water, introduction to pH and buffering. Slides: Water and pH
An overview/review of basic chemistry concepts, including atoms, isotopes, ions, electrons and reactivity, chemical bonds, and reactions. Slides: Atoms & Bonds